This invention relates in general to instruments for scanning samples for specimens and, in particular, a system for scanning samples or specimens with improved characteristics.
Profiling instruments were first developed for the purpose of characterizing surfaces in terms of roughness, waviness and form. In recent years, they have been refined for precise metrology in the measurement and production and control of semiconductor devices. Profiling instruments are also used outside the semiconductor industry, for example, for scanning and sensing optical disks, flat panel displays, and other devices.
One type of sensor used in profiling instruments includes sensors that are described in this application as being stylus probe instruments or stylus probe measurement devices. Stylus probe instruments are defined as including scanning probe microscopes. Scanning probe microscopes include atomic force microscopes, scanning tunneling microscopes and the like. Additionally, stylus probe instruments can include stylus profilometers, such as those described in U.S. patent application Ser. No. 08/598,848 entitled "Dual Stage Instrument for Scanning a Specimen" and filed Feb. 9, 1996, which is incorporated herein by reference. Another type of stylus profilometer is described in Wheeler et al. U.S. Pat. No. 5,309,755, which is incorporated herein by reference.
It should be noted that stylus probe instruments have traditionally been very slow, where an image of a surface could easily require minutes of data acquisition. The advantage of stylus probe instruments is that they can be made to be very precise. In the case of scanning probe microscopes, such as atomic force microscopes, the sensors have a very limited range in X, Y and Z--typically, from Angstroms to 100 microns in X and Y and a maximum of ten microns range in Z. Typical stylus profilometers have a range of 1 micrometer to 500 micrometers in X and Y and hundreds of microns in Z. Recently, a new stylus profilometer class of tools was introduced capable of scanning from 0.01 micrometers to 500 millimeters in X and Y and hundreds of microns in Z. This was described in the U.S. Patent Application "Dual Stage Instrument for Scanning a Specimen" discussed above.
It is desired to have a system that reduces the slowness and increases the throughput of the profiling instrument.